While experts acknowledge that Iran is “playing with fire” against the best navy in the world, don’t expect these incidents to stop any time soon.

“The number of unsafe, unprofessional interactions for first half of the year is nearly twice as much as same period in 2015, trend has continued. There’s already more in 2016 than all of 2015,” Commander Bill Urban of the Navy’s 5th fleet told Business Insider in a phone interview.

Urban stressed that despite the Iranian navy fast-attack craft being several orders of magnitude less potent than US Navy ships, the threat they pose in the gulf is very real.

“Any time another vessel is charging in on one of your ships and they’re not talking on the radio … you don’t know what their intentions are,” said Urban.

Urban confirmed that Iran sends small, fast attack ships to “swarm” and “harass” larger US Naval vessels that could quite easily put them at the bottom of the ocean, but the ships pose a threat beyond firepower.

According to Urban, these ships are “certainly armed vessels with crew-manned weapons, not unarmed ships. I wouldn’t discount the ability to be a danger. A collision at sea even with a much larger ship is always something that could cause damage to a ship or injure personnel.”

In the most recent episode at sea, Urban said that an Iranian craft swerved in front of the USS Firebolt, a US Coastal Patrol craft, and stopped dead in its path, causing the Firebolt to have to adjust course or risk collision.

The messages Iran wants to send

Picture of US Sailors captured by Iranian fast-attack craft in the Gulf. | Released by Iranian Revolutionary Guards on Jan. 13, 2016.

“In my view, Khamenei (Supreme Leader of the Islamic Republic) decided it’s time to send a message — I’m here and I’m unhappy,” Cliff Kupchan, Chairman of Eurasia Group and expert on Iran, told Business Insider in a phone interview.

According to Kupchan, the Iranian navy carries out these stunts under directions straight from the top because of frustrations with the Iran nuclear deal. Despite billions of dollars in sanction relief flowing into Iran following the deal, Kupchan says Iran sees the US as “preventing European and Asian banks from moving into Iran and financing Iranian businesses,” and therefore not holding up their end of the Iran nuclear deal.

But despite their perception that the US has under delivered on the promises of the Iran nuclear deal, Kupchan says Iran will absolutely not walk away from the deal, which has greatly improved their international standing and financial prospects.

The lifting of sanctions on Iran’s oil has resulted in “billions in additional revenue … They’re not gonna walk away from that.”

So Iran seems to be simply spinning their wheels to score political points with hardliners, but what if the worst happens and there is a miscalculation in a conflict between Iranian and US naval vessels resulting in the loss of life?

The coastal patrol ship USS Squall, one of the ships harassed by the Iranians. | US Navy photo by Mass Communications Specialist Michelle Turner

“The concern is miscalculation,” said Kupchan. “Some guy misjudges the speed of his boat, people could die. There is a lot on the line.”

According to Kupchan, as well as other experts on the subject, Iran’s navy doesn’t stand a serious chance against modern US Navy ships.

“Iran Revolutionary Guard Corps boats and the Iranian Navy are not very capable or modern,” said Kupchan. The fast-attack craft we’ve seen challenge US Navy boats have simply been older speed boats, some Russian-made, outfitted with guns.

The Iranian craft can certainly bother US Navy ships by risking collisions and functioning as “heavily armed gnats, or mosquitoes” that swarm US ships, but a recent test carried out by the Navy confirms that the gunships wouldn’t have much trouble knocking them out of the water. The ensuing international incident, however, would dominate headlines for weeks.

“The wood is dry in US and Iranian relations,” said Kupchan, suggesting that a small miscalculation could spark a major fire, and that harassing these ships is “one of the ways the Iranian political system lets off steam.”

“Hardliners on both sides would go nuts,” said Kupchan, referencing both the conservative Islamist Iranians and the conservative US hawks who would not pass up any opportunity to impinge Obama over his perceived weakness against the Iranians.

Yet Kupchan contends that even a lethal incident would not end the deal. Both sides simply have too much riding on the deal’s success: Obama with his foreign policy legacy, and Iran with their financial redemption and status in the region as the main adversary to Western powers.

However Iran’s Khamenei may be sending a second message to incoming US leadership, specifically Hillary Clinton, who seems likely to be the next commander in chief. “They know Clinton is tough,” said Kupchan, and Khamenei may be addressing Clinton with a second message, saying “Madame Secretary, I’m still here, I know you’re tough, but I’m ready.”

For now, Kupchan expects these incidents at sea to carry on as Iran vents about their larger frustrations, and that a violent exchange would “not be the end of the deal,” or the start of a larger war, “but a serious international incident.”